The original NuForce Icon was a very nice, compact unit that served as an introduction to USB DAC's for me. As my headphones improved, and I acquired more 24/96 audio tracks, I started to see some limitations for it in my system, and the HDP version has come along to take care of all of those issues. With a DAC that offers better quality that $500+ players out there, and a headphone amp that was able to drive a difficult load, the HDP comes out as a fantastic bargain in my opinion. For anyone that has a PC audio system, or a headphone system, and is looking for a DAC or an amplifier, the HDP gets a high recommendation from me.